Rubber composition for tires with improved winter performance and abrasion resistance

Abstract

The present invention relates to a cross-linkable rubber composition, a cross-linked rubber composition obtained by cross-linking such a rubber composition, a method of preparing a tire and a tire. A cross-linkable rubber composition comprises, per hundred parts by weight of rubber (phr): 100 phr of a diene-based elastomer component with an average molecular weight Mn in a range of ≥100000 to ≤5000000 g/mol and a homopolymer of polybutadiene, wherein the homopolymer of polybutadiene has an average molecular weight Mn in a range of ≥10000 to ≤45000 g/mol and a glass transition temperature Tg in a range of ≥−110° C. to ≤−60° C.

The invention claimed is: 
     
       1. A cross-linkable rubber composition, the cross-linkable rubber composition comprising, per hundred parts by weight of solid rubber (phr):
 100 phr of a diene-based elastomer component with an average molecular weight Mn in a range of ≥100000 to ≤5000000 g/mol and 
 a homopolymer of polybutadiene, 
 wherein the homopolymer of polybutadiene has 
 an average molecular weight Mn in a range of ≥10000 to ≤45000 g/mol and 
 a glass transition temperature Tg in a range of ≥−110° C. to ≤−60° C., 
 
       wherein the rubber composition comprises ≥5 to ≤15 phr of the homopolymer of polybutadiene, and 
       wherein the diene-based elastomer component comprises ≥40 phr to ≤90 phr of a styrene-butadiene rubber component comprising a first styrene-butadiene and a second butadiene rubber that is different from the first styrene-butadiene rubber and ≥10 phr to ≤60 phr of a combination of a natural rubber and a butadiene rubber. 
     
     
       2. The rubber composition according to  claim 1 , wherein the homopolymer of polybutadiene has a vinyl (1,2-) content in a range of ≥0 to ≤40 wt %. 
     
     
       3. The rubber composition according to  claim 1 , wherein the homopolymer of polybutadiene has a melt viscosity of range of ≥15 to ≤500 Pa s at 38° C. 
     
     
       4. A cross-linked rubber composition obtained by cross-linking the cross-linkable rubber composition according to  claim 1 . 
     
     
       5. The cross-linked rubber composition according to  claim 4  with a tan δ at 0° C. of ≥0.16 to ≤0.35. 
     
     
       6. The cross-linked rubber composition according to  claim 4  with a glass transition temperature Tg of ≥−50° C. to ≤−35° C. 
     
     
       7. The cross-linked rubber composition according to  claim 4  with an abrasion resistance of ≤75 mm 3 . 
     
     
       8. The cross-linked rubber composition according to  claim 4  with an elastic modulus G′ at −20° C. of ≥25 to ≤40 MPa. 
     
     
       9. A method of preparing a tire, comprising the steps of:
 providing a tire assembly comprising a cross-linkable rubber composition according to  claim 1 ; and 
 cross-linking at least the cross-linkable rubber composition in the tire assembly. 
 
     
     
       10. A tire comprising a tire tread, characterised in that the tire tread comprises a cross-linked rubber composition according to  claim 4 .